CVE-2026-77581

Description

BentoPDF is a client-side PDF toolkit that is self hostable. In 2.8.6 and earlier, the certificate and timestamp CORS proxy in cloudflare/cors-proxy-worker.js uses isPrivateOrReservedHost() to validate a supplied hostname separately from the DNS resolution used by fetch(targetUrl), allowing an attacker-controlled hostname to resolve to an internal or reserved destination after validation. A certificate-like path can satisfy ALLOWED_PATH_PATTERNS, and direct clients can forge the browser-oriented Origin header. Deployments without PROXY_SECRET skip the optional signature check, while the signature is an anti-abuse measure rather than a destination-security boundary. The proxy has a 10 MB response limit and can relay response bodies from reachable destinations. The advisory identifies both the official Worker deployment and self-hosted instances as impacted where the Worker execution environment can reach internal or reserved destinations. This vulnerability is fixed in 2.8.7.

Overview

State: PUBLISHED
Assigner (CNA): GitHub_M
CVSS severity: HIGH
CVSS score: 8.6 / 10
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
Effective score: 8.6 / 10 HIGH source: CNA overview
CWE(s): CWE-918
Reserved: 2026-08-20
Published: 2026-09-24 15:23 UTC
Last updated: 2026-09-24 15:37 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/77xxx/CVE-2026-77581.json
Linked Threat: CVE-2026-77581 — BentoPDF: SSRF in cors-proxy-worker.js via DNS-based hostname allowlist bypass

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-86229
Assigner: GitHub_M
Published: Sep 24, 2026, 3:23:18 PM
Updated: Sep 24, 2026, 3:37:29 PM
EUVD base score (CVSS 3.1): 8.6 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
EUVD-reported EPSS: 0.0000
Vendors: alam00000
Products: bentopdf (< 2.8.7)

ENISA description: BentoPDF is a client-side PDF toolkit that is self hostable. In 2.8.6 and earlier, the certificate and timestamp CORS proxy in cloudflare/cors-proxy-worker.js uses isPrivateOrReservedHost() to validate a supplied hostname separately from the DNS resolution used by fetch(targetUrl), allowing an attacker-controlled hostname to resolve to an internal or reserved destination after validation. A certificate-like path can satisfy ALLOWED_PATH_PATTERNS, and direct clients can forge the browser-oriented Origin header. Deployments without PROXY_SECRET skip the optional signature check, while the signature is an anti-abuse measure rather than a destination-security boundary. The proxy has a 10 MB response limit and can relay response bodies from reachable destinations. The advisory identifies both the official Worker deployment and self-hosted instances as impacted where the Worker execution environment can reach internal or reserved destinations. This vulnerability is fixed in 2.8.7.

EUVD references (4)

Affected products (1)

Vendor	Product	Versions	Platforms
alam00000	bentopdf	`< 2.8.7` (affected)	—

Vendor references (4)

References embedded in the original CVE record by the assigning CNA.

https://github.com/alam00000/bentopdf/security/advisories/GHSA-5xjf-rr5x-pcfj x_refsource_CONFIRM
https://github.com/alam00000/bentopdf/commit/45496fcd2ed6e02dcdde0d3839cc5024c091760c x_refsource_MISC
https://github.com/alam00000/bentopdf/commit/58cd1a8893bfe06e4a59a72adc2e7db00a8b9266 x_refsource_MISC
https://github.com/alam00000/bentopdf/releases/tag/v2.8.7 x_refsource_MISC

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Microsoft Update Catalog

web:catalog.update.microsoft.com

Welcome to the Microsoft Update Catalog site. We want your feedback! Visit our newsgroup or send us an email to provide us with your thoughts and suggestions. To get started using the site, enter in your search terms in the Search box above or visit our FAQ for search tips. |Newsgroup|Send us your feedback

2026-09-25 10:11 UTC
Microsoft Patch Tuesday March 2026 - 78 Vulnerabilities Fixed ...

web:cybersecuritynews.com

Microsoft released its March 2026 Patch Tuesday security update on March 10, 2026 , addressing 78 vulnerabilities across a wide range of products, including Windows, Microsoft Office, Azure, SQL Server, and .NET.

2026-09-25 10:11 UTC
CVE-2026-77581 - Exploits & Severity - Feedly

web:feedly.com

News CVE-2026-77581 : CWE-918: Server-Side Request Forgery (SSRF) in alam00000 bentopdf

2026-09-25 10:11 UTC
Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-09-25 10:11 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-25 10:11 UTC
Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws

web:www.bleepingcomputer.com

Today is Microsoft's February 2026 Patch Tuesday with security updates for 58 flaws, including 6 actively exploited and three publicly disclosed zero-day vulnerabilities.

2026-09-25 10:11 UTC
Microsoft March 2026 Patch Tuesday fixes 2 zero-days, 79 flaws

web:www.bleepingcomputer.com

Today is Microsoft's March 2026 Patch Tuesday with security updates for 79 flaws, including 2 publicly disclosed zero-day vulnerabilities.

2026-09-25 10:11 UTC
Critical Patches Issued for Microsoft Products, August 11, 2026

web:www.cisecurity.org

<p>Multiple vulnerabilities have been discovered in Microsoft products, the most severe of which could allow for remote code execution. Successful exploitation of the most severe of these vulnerabilities could result in an attacker gaining the same privileges as the logged-on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or ...

2026-09-25 10:11 UTC
August's Patch Tuesday is a monster: 751 fixes, with an exploited ...

web:www.computerworld.com

August's Patch Tuesday is a big one: 751 fixes, an exploited WinSock flaw and plenty of critical Windows, Office and Exchange issues.

2026-09-25 10:11 UTC
Patch Tuesday September 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's September 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-09-25 10:11 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-77581.json.

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